Transmissions for vehicles may include a parking lock mechanism. Typically, the parking lock mechanism is included in an automatic transmission. The parking lock mechanism locks an output shaft of the transmission to prevent the vehicle from rolling when the vehicle is not in use. The parking lock mechanism typically includes a lock gear fitted to the output shaft of the transmission. Alternately, the lock gear may be drivingly engaged with the output shaft. When directed by an operator of the vehicle or a control system of the vehicle, a pawl engages the lock gear, which prevents the vehicle from rolling.
Occasionally, when the parking lock mechanism is engaged, the output shaft (and thus the parking lock mechanism) of the vehicle may be subjected to an abnormally large rotational force. As non-limiting examples, the abnormally large rotational force may be applied to the output shaft when an object collides with the vehicle or when the vehicle is parked at an excessive incline. When the abnormally large rotational force is applied to the output shaft, the parking lock mechanism is typically damaged, requiring repair of the parking lock mechanism.
It would be advantageous to develop a parking lock mechanism for a transmission that releases when the output shaft of the transmission is subjected to an abnormally large rotational force.